Conveyor Chain Technical Qualities

FB conveyor chain manufacturing is focused on metric pitch conveyor chains that include International Standards DIN 8167/ISO 1977 M series, DIN 8165/ISO1977 FV series and SMS1968 S series. In addition we can offer different materials and manufacturing methods to suit the most demanding conveyor chain applications.

Increasing the life of conveyor chain running on wear strips

Do you have conveyor chain that often runs on metal or plastic wear strips? If you do then it is important that the hardness of these surfaces and the finished condition of the conveyor chain link plates is carefully considered. By running a chain on a metal conveyor chain wear strip, that is too hard, you will cause the conveyor chain side plates to wear quickly and thereby dramatically reduce the life of the chain. Conversely, should you be running your conveyor chain on a plastic wear strip then the life of the wear strip will be greatly increased by removing all the sharp edges of the conveyor chain link plates by surface tumbling.

What is surface tumbling?

Tumbling is a simple process where the finished conveyor chain links plates are placed in a container and ‘barreled’ in a special abrasive media so that they continually rub against each other and the abrasive stones. After some time the plates will have been polished and all the sharp edges will have been removed. The illustration below shows how the sharp corners of the tumbled plates become round and smoother; which ultimately will result in much longer wear strip life.

If you would like to increase the life of plastic conveyor chain wear strips then please ask for your conveyor chain side plates to be tumbled. The potential savings in replacement wear strips, costly machine down time and engineer labour costs will be far greater than the small increase in the basic price of the ‘tumbled’ conveyor chain.

Hardening of conveyor chain

Induction hardening is a type of heat treatment where the carbon steel part is heated by induction heating and then quenched. This highly controllable method is consistently repeatable; resulting in a high quality conveyor chain. With the compressed surface and increased depth of hardness of induction hardened parts, compared with standard case hardening, we increase the wear life and fatigue resistance of FB conveyor chain components. Conversely the core strength of the material is unaffected and remains soft and ductile which results in a chain with greater overall resistance to shock loads.

The induction hardening process enables us to selectively harden only the working areas of our conveyor chain pins and conveyor chain bushes leaving their ends soft and ductile which can be clearly seen in the pictures of a conveyor chain Pin and bush above . Having these softer areas is vitally important when it comes to pressing these round components into the side plates. Using this method we can increase the amount of press fit between the outer side plates and the pins and the inner side plates and the bushes. By doing so we significantly increase the strength of FB conveyor chain. In addition when riveting our conveyor chain pins the amount of material displaced is far greater compared to that achieved with a fully case hardened pin. This gives us much higher push out values and again increases the strength of FB conveyor chain.

Benefits of welded conveyor chain

By using FB conveyor chain with welded pins and bushes you may be able to reduce the chain size selected. For example: FV250A160 could be replaced by FV180A160. This chain would be 40% lighter and take up far less space. Alternatively if you have a problem application then using a welded pin and bush conveyor chain would increase the life of your conveyor chain. How do we do that?

All materials used in FB conveyor chain have been specially selected with their weldability in mind. This was achieved with the considerable help of leading Scandinavian steel producers and welding specialists from the University of Lappeenranta. By not only selecting the correct material but by also using automatic welding machines we produce high quality, reliable and consistent results. These machines give us the ability to keep the welding process, the welding temperature and energy usage under tight control. Each size and type of conveyor chain has its own welding parameters preloaded into these machines which minimizes the likelihood of human error. Due to our highly developed welding technology we are able to keep the heat affected zone to an absolute minimum which results in a finished conveyor chain that will stand the test of time.

In addition to the welding techniques employed we carefully protect the ends of our pins and bushes from hardening thereby improving the weldability of our conveyor chain, conveyor chain pins and conveyor chain bushes.

FB conveyor chains with welded pins and bushes not only have high durability against shock loads but they also have tensile strengths that are 30% higher than ISO Standard conveyor chains commonly found in the marketplace.

For example: Breaking load of FB M315-conveyor chain

ISO Standard

FB Round riveted pin

FB Welded pin only

FB Welded pin and bush

315 kN

320-350 kN

380-410 kN

440-470 kN

In 2004 following considerable research, development and testing, FB changed the design of the welded pin used on our larger tensile strength conveyor chains. This means that those conveyor chains above M160, M112, FV140 and A12,5 now have round ends without locating shoulders. This positive step has produced a construction that has the following benefits:

Improved the welding connection

Lighter presetting of the side plates

Further improved the breaking load

Further improved fatigue strength endurance

For example: The force needed to break the rivet / weld of FB M315-conveyor chain

ISO Standard

FB Round riveted pin

FB Round welded pin

Welded – new pin construction

Not specified

Abt. 12.000 kg

Abt. 15.000 kg

Abt. 17.000 kg

Side plate material selection

The major requirements of a high quality conveyor chain are excellent wear life with optimum strength and consistently high fatigue resistance. In order to achieve such benefits we not only press out and manufacture the various component parts to very close tolerances but we firstly select high grade steels that, once heat treated, will continue ensure the desired end results.

We have spent many years working with Scandinavia’s leading steel producers refining and honing our steel selections so that we can confidently manufacture high quality conveyor chains for use in the most demanding and arduous applications.

We believe that selecting the correct materials are so important for high quality conveyor chain that we regularly manufacture our chain using 3 different side plate materials. By doing so we can ensure that the resultant conveyor chains will provide optimum performance matched to the required application.

Key to our selection of materials is their weldability.

Standard Steel

Similar to St52-3 and S355J2G3 with higher yield strength 410 N/mm²

Carbon content under 0,20 %

Hardness circa 180 HB

Very good for welding

Produced in Scandinavia

FB1000

This side plate material is often used in applications which require where there is greater wear on side plates area or where extra strength is required.

Similar to StE500 with higher yield strength 520 N/mm²

Carbon content 0,25 – 0,30%

Hardness circa 220 HB

Very good for welding

Produced in Scandinavia

Conveyor chain side plate materials used by FB Ketju

Materials

% Carbon

Yield Strength ReH N/mm²

Tensile Strength ReH N/mm²

Weldability

Hardenability

Standard

<0.20%

355

490 > 630

Very Good

Poor

FB1000

0.15% to 0.20%

520

600> 800

Very Good

Very Good

Typical materials used by other European conveyor chain manufacturers

Materials

% Carbon

Yield Strength ReH N/mm²

Tensile Strength ReH N/mm²

Weldability

Hardenability

ST60

0.40%

315

570 > 710

Very Poor

Good

ST70

0.50%

345

670 > 830

Very Poor

Good

C45

0.45%

305

580

Very Poor

Very Good

Lubrication

In order for a conveyor chain to perform well the bearing surface must be lubricated.

Although all FB conveyor chains are lubricated before they leave the factory, re-lubrication should be carried out after installation and at regular intervals as a preventative measure. Correct lubrication will minimize power absorbtion, wear rate, corrosion and noise.

In normal conditions and operating temperatures a quality mineral oil with medium viscosity will e.g. SAE 20W50 will suffice. However, for specific application environments see the information below.

Industry

Conveyor chains operating in certain industries will require specialist lubricants to avoid contamination or spoiling of the product being conveyed. Those working in the food, tobacco, water, textiles, hospital and nuclear industries should contact a lubricant specialist for advice.

Temperature

Conveyor chains operating in low temperatures between -60° and 0° C require specialist low temperature water repellent grease to prevent condensation from freezing on the chain and halting articulation.

Up to 160° C a wet film lubricant should be used. These types of lubricants are usually solid greases which are dispersed in a chlorinated hydrocarbon solvent. This allows the lubricant to penetrate into the joints of the chain.

For temperatures over 160° C a dry-film non-carbonizing lubricant should be used.

Dusty Environments

Conveyor chains operating in dusty environments should be lubricated with a dry-film lubricant to prevent dust adherance. The chain must be periodically cleaned and re-lubricated to remove any build up.

Water

Conveyor chains in water plants typically operate above the water level and so require a lubricant that is adhesive enough not to drip into and, therefore, contaminate drinking water. Heavy greases are usually the most effective.

Conveyor chains operating in sewage treatment works are often submerged in the water and so it is impossible to lubricate them regularly. In this case those responsible for ordering chains should ask for materials and manufacturing processes which are specifically suited to continuously wet environments. Where chains are accessible for lubrication, water-repellent grease should be used.

Solvents

Re-lubrication of conveyor chains exposed to solvents is not usually possible as it might contaminate the product i.e. the solvent. Lubrication suppliers should be contacted for specialist advice.

Stainless steel pins and bushes

Many chain conveyor applications involve moving products with a high moisture content such as bark, woodchip and peat. In such cases the internal surfaces of the selected conveyor chain can become rusty and corroded. This is particularly the case around the bearing surfaces of the pins and bushes of carbon steel conveyor chain.

Making a chain completely from stainless steel would solve this problem but the higher wear rate and significantly reduced tensile strength generally preclude this option. The FB answer is the development and manufacture of a carbon steel conveyor chain that can be constructed using stainless steel pins and bushes.

This unique approach, using a combination of components manufactured from different materials, enables FB to successfully overcome the difficulties of conveyor chain applications in a moisture ridden environment.

Production options and customisation

Not every chain conveyor application is the same, the type and volume of product being conveyed places many different demands on the conveyor chain. It is not unusual for the conveyor chain size to be increased to cope with the more demanding chain conveyor applications.

FB have a number of options for chain conveyors working in arduous applications. We are able to vary the build and make-up of the chain and alter the surface finish with ‘tumbled’ side plates. Should corrosion be an issue we can manufacture zinc-plated conveyor chain or stainless steel conveyor chain.